Using PDO instead of mysql_

[popcop]

Im currently using this code...

    // connect to and select the database
    @mysql_connect($host,$user,$password) or die("&success=no&");
    @mysql_select_db($dbname) or die("&success=no&");

    // query the database and return an array of data
    $result = @mysql_query("SELECT * FROM $tablename WHERE rand = $rand") or die("&success=no&"); 

i keep getting told not to use it and to now use PDO, can someone please show me exactly how i change the above code to PDO